1. Field of the Invention
The present invention generally relates to paint spray booths and more particularly is concerned with a method for automatically cleaning the floor and sub-floor regions of the booth.
Mass produced products such as automobiles are usually painted in spray booths where the parts are conveyed serially through the booth, and paint is applied either manually or by using robotics. The booths are usually quite long and narrow and totally enclosed except for the openings where the parts enter and exit the booth. Because of common problems associated with spray painting, the booths are usually built with some unique characteristics.
One problem is that a large percentage of the paint never reaches the part being painted but appears as overspray in the air. The overspray must be removed from the booth so that it will not fall back on the painted part or the interior of the booth. To remove the overspray from the air, many booths are provided with a vertical, laminar air flow which is pumped into the booth through a perforated ceiling and passes down through a perforated floor. This creates a constant draft which carries the overspray beneath the floor and into a sub-floor where, in many conventional systems, the overspray in the draft mixes with a cleaning agent, such as water, and the agent carrying the overspray is then removed from the sub-floor to be disposed of properly. Federal law regulates the emissions from paint spray booths in order to prevent a large concentration of paint particles in the air exhausted to the environment. With this in mind it becomes apparent that the booth must be kept clean and the overspray removal process must be maintained in good working order.
Today, it is common for paint spray booths to have a sub-floor region beneath a perforated floor, usually steel grating, wherein the paint overspray particles are removed from the draft. This removal process takes place in a scrubber section which is a part of the sub-floor. As the overspray particles are removed from the draft, by mixing with water in the sub-floor scrubber section, a sludge will start to build up on the sub-floor structures. The paint particles will also make the floor sticky and the particles will tend to obstruct the air flow through the perforated floor. While the paint spray booth is not in use the floor and sub-floor must be cleaned of this sludge build-up and paint overspray. In the past, the floor grating was removed manually from the paint booth and cleaned by dipping the grating sections into a liquid bath, letting them soak and then replacing them in the booth. Having to continually remove and replace the grating became cumbersome and has been replaced with what is in use today.
Presently, high pressure jets of water are applied to the floor grating and the sub-floor structure to remove overspray and paint sludge. It can take many hours to clean the floor grating and sub-floor structure using this method because production booths can be hundreds of feet long. Cleaning is normally done manually during the night shift or on weekends resulting in very high costs.
Consequently, a need exists to improve the method by which the floor and sub floor structure of a paint spray booth are cleaned. A method is needed that will not require manual operation; that will take less time than a manual operation; that will operate within the confines of a typical paint spray booth structure; and a method that will not require a large capital investment.